Abstract: A series of experiments were conducted to improve the induction of in vitro tuberization of potato. The results showed that a length of shoot with 3 to 4 nodes cut off from in vitro potato plantlet could be proliferated to 3^2 to 4^2 shoots in 2 to 3 weeks when it was cultured in static shallow liquid Murashige-Skoog medium which had been added with some growth agents. Then these shoots would initiate tuberization in 1 to 3 weeks just after replacing the existing medium by the tuber inducing medium into the same container. In another 3 to 4 weeks, these tuberlets matured and were capable of sprouting. They could be harvested as virusfrce prebasic seedpotatoes for cither further propagation or direct utilization. By this improved method, the process of the propagation of virusfrce tuberlets was much accelerated. Also the cost of material and labor was decreased and the quantity of the virusfree prebasic seedpotatoes was greatly increased. The effects of hormones and the application of the improved management to the production of the virusfree seedpotatoes, are discussed in this paper.

Key words: in vitro tuberization